1. Field of the Invention
The subject invention generally pertains to a movable barrier and more specifically to a barrier adapted for various uses including, but not limited to, use as a door, machine guarding, and welding flash shield.
2. Description of Related Art
At some work centers, various barriers are often used for protecting nearby personnel from the hazards of moving or otherwise hazardous machinery and materials. Examples of such hazards may include, but are not limited to, large or fast moving parts traveling along a conveyor, machining centers throwing chips or coolant, welders emitting eye-damaging light, power washers spraying water, presses, punches, and brakes. If periodic access to such work centers is needed, the protective barrier may be designed with a feature that allows the barrier to be readily moved. For example, the barrier may include a panel that swings or otherwise moves between an open and closed position.
However, moving a panel to its open position may place the panel in a location that interferes or creates problems with other operations associated with the work center. If the panel swings open and closed, dedicated floor space may be needed just for the door""s operation. This can be a serious problem in situations where space is limited. Having a vertically moving panel that rises to its open position may solve the problem of limited floor space. However, if the panel rises to its open position, the raised panel may interfere with loading or unloading parts to and from the work center. In some cases, reaching underneath a raised panel may be awkward. Also, there may be insufficient headroom to lift a part up and over the raised panel. If the part is heavy and lifted with a jib hoist, a large heavy load swinging high overhead creates a hazard in itself.
In many applications, a preferred design would be a panel that opens by descending to a lowered position. Unfortunately, such a panel may be difficult to raise and lower without a drive mechanism operating on both lateral edges of the panel. Such a drive mechanism, if it even exists, may be costly and/or may involve installing an overhead drive shaft. Such a shaft may create some of the same problems associated with a panel having a raised open position.
In some embodiments, a barrier maintains a movable curtain in a proper orientation by coupling the curtain to two curtain guide members against which a pliable elongate member applies both an upward force and a downward force.
In some embodiments, the tension in a pliable elongate member horizontally compresses a curtain header.
In some embodiments, a pliable elongate member that helps support the weight of a curtain passes through a curtain header of the curtain.
In some embodiments, two pliable elongate members share the load of supporting a curtain""s weight substantially equally, yet the tension in one of the pliable elongate members is appreciably greater than that in the other.
In some embodiments, a barrier includes a curtain that moves upward from a closed position to an open position.
In some embodiments, a barrier includes a curtain that moves downward from a closed position to an open position.
In some embodiments, to help maintain a curtain in a proper orientation, a pliable elongate member extends above and below a leading edge of a curtain and transits from one side of the curtain to an opposite side.
In some embodiments, a barrier is at times inhibited from opening by coupling the barrier""s curtain to two pliable elongate members, which are wrapped in opposite directions around a powered drum.
In some embodiments, a barrier is inhibited from opening upon losing tension in a pliable elongate member that was intended for supporting the weight of the barrier""s curtain.
In some embodiments, a barrier includes a curtain holder that helps collect a lower, slack portion of the curtain as the curtain ascends to its open position.